Cosmetic skin care methods and compositions for conditioning human skin by topical application of cosmetic compositions containing gum mastic.
Sebum is skin oil which is produced by sebocytes (cells of the sebaceous glands in the skin) and is then secreted to the skin surface. A frequent, undesirable skin condition is xe2x80x9coily skin,xe2x80x9d the condition which results from the excessive amount of sebum on the skin. Oily skin is associated with a shiny, undesirable appearance and a disagreeable tactile sensation and affects various age groups. Cosmetic products which can condition the skin to provide sebum control is therefore highly desirable.
In recent years, consumer demand for xe2x80x9cnaturalxe2x80x9d products has led to the use of plant extracts in various skin care compositions. The prior art discloses gum/resins and oils from plants for various uses. For example, WO 91/10196 assigned to Parfums Christian Dior (hereinafter xe2x80x9cDior ""196xe2x80x9d), discloses the use of forms of the resin guggul, an extract from a plant of the genus Commiphora, originating in India. Dior ""196 discloses the use of guggul as a cosmetic agent for improving the appearance of the skin surface and in particular, for reducing the depth of wrinkles and making fine lines disappear.
U.S. Pat. No. 5,690,948 issued to McCook et al. (hereinafter xe2x80x9cMcCook ""948xe2x80x9d), discloses the use of ethyl acetate extracts of the gum/resin guggal, referred to as gugulipid. McCook ""948 discloses the use of gugulipid and alcoholic fractions thereof in antisebum and antioxidant compositions.
Gum mastic, which may be obtained as a trunk exudate of the species Pistacia lentiscus L., an evergreen shrub of the Anacardiaceae family, has been produced since ancient times on the island of Chios, Greece. Components of gum mastic include xcex1-pinene, camphene, xcex2-pinene, sabinene, myrcene, xcex4-3-carene, limonene, eucalyptol, Yy-terpinene, p-cymene, terpinolene, terpinene-1-ol-4 and xcex1-terpineol. See Fragrance Raw Materials Monographs, Mastic Absolute. Certain terpenoids of gum mastic have also been identified and isolated. See xe2x80x9cTriterpenoids From Gum Mastic, The Resin of Pistacia Lentiscus,xe2x80x9d Phytochemistry, Vol. 30, No. 11, pp. 3709-3712, 1991.
U.S. Pat. No. 5,422,100 issued to Eliaz et al. (hereinafter xe2x80x9cEliaz ""100xe2x80x9d), discloses the use of gum mastic as a carrier for hair and skin conditioning methods and products. In particular, Eliaz ""100 teaches topical application of a treatment agent to the skin for promoting hair growth, preventing, stopping or minimizing hair loss, conditioning the hair and scalp, thickening the hair, treating dandruff, smoothing skin, treating seborrheic dermatitis, treating psoriasis and like condition, and possibly including uses such as the healing of wounds in the skin. The gum mastic carrier provides a medium for the treatment agent with a capability for penetrating into the skin and/or hair follicles.
U.S. Pat. No. 5,637,290 issued to Sodis et al., discloses the use of natural mastic from chios, extract mastic oil, or synthetic mastic agents for production of toothpaste, mouthwash, mouth deodorizers, suntan lotions, hair products, and cosmetics.
Practically all penetration and absorption into the skin occurs via the hair follicles and the sebaceous glands. Cosmetics Science and Technology, pp. 46-47, vol. 1, Krieger Publishing Co., 1992. Therefore, an ideal cosmetically beneficial composition for delivery of an active to the skin delivers the active such that it adheres to skin or hair. It is well known in the art to use emulsions because of their ability to deliver both oil and water to the skin and hair. Conventionally, actives have been delivered in water-in-oil or oil-in-water emulsions, with oil-in-water emulsions being preferred because of the desirable aesthetic and elegant properties such as rich and creamy, yet non-greasy skin feel. Id. at 47.
The prior art discussed above does not disclose cosmetic mediums that provide enhanced delivery of plant extracts to the skin for a dual benefit of sebum suppression and anti-aging benefits. Therefore, a need remains for such cosmetic products containing cost-effective and readily available natural ingredients.
The present invention includes an oil-in-water cosmetic skin care emulsion composition comprising:
(a) from about 0.001 wt. % to about 10 wt. % of solubilized gum mastic
(b) a volatile, water miscible solvent; and
(c) a cosmetically acceptable vehicle.
Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word xe2x80x9cabout.xe2x80x9d All amounts are by weight of the oil-in-water emulsion, unless otherwise specified.
The term xe2x80x9cskinxe2x80x9d as used herein includes the skin on the face, neck, chest, back, arms, hands, legs, and scalp.
The term xe2x80x9cgum masticxe2x80x9d as used herein means the resin from the species Pistacia lentiscus L., an evergreen shrub of the Anacardiaceae family, found on the island of Chios, Greece.
The term xe2x80x9csolubilizedxe2x80x9d as used herein means that at least 90% of gum mastic present in the final composition is solubilized.
The term xe2x80x9cwater misciblexe2x80x9d as used herein means that at least 95% of solvent present in the final composition is miscible in water.
According to the present invention, solubilized gum mastic controls sebum secretion and/or controls oily skin and prevents skin wrinkles and laxity.
All amounts are by weight of an oil-in-water emulsion, unless otherwise indicated.
Sebum is oil produced by sebocyte cells of the sebaceous glands. Inhibition of sebocyte lipogenesis reduces excretion of sebum, thereby reducing and/or controlling oily skin. Alternatively, enhancing collagen production aids in preventing skin wrinkles and laxity. It has been found as part of the present invention that solubilized gum mastic unexpectedly possesses sebum suppression activity through inhibition of sebocyte lipogenesis as well as providing anti-aging benefits through enhanced collagen production.
Gum mastic in crystal form may be obtained from Sigma Chemicals or Spectrum. Premixed solutions of gum mastic (e.g. Lentisque Absolute) may be obtained from Biolandes Parfums. Relative to extracts such as gugulipid, gum mastic is inexpensive and therefore cost-effective in use in cosmetic skin care compositions.
Gum mastic is oil soluble and is therefore dissolved in a suitable solvent in the inventive compositions. In the preferred embodiment, volatile water miscible solvents are used because such solvents evaporate after application to the skin. The gum mastic in the inventive compositions therefore remains in contact with the skin even after evaporation of the solvent until the gum mastic penetrates into the skin and hair follicles, providing both suppression of sebum and anti-aging benefits. In contrast, non-volatile, water immiscible solvents such as isopropyl myristate as disclosed in Eliaz ""100, do not evaporate. Therefore, even after application onto the skin, the gum mastic would remain trapped in the solvent such that only a final diluted amount of gum mastic would penetrate the hair follicles.
Suitable volatile, water miscible solvents include ethanol, methanol, propanol, isopropyl alcohol and mixtures thereof. Ethanol is preferred due to commercial availability. To realize a cosmetic benefit, the ratio of gum mastic to solvent can vary from 1:75, preferably from 1:50, and most preferably from 2:1.
Solubilized gum mastic is present in the inventive compositions between 0.001 to 10% by weight of the composition, preferably from 0.01 to 1%, and most preferably from 0.01 to 0.05%.
Although other forms are contemplated to be within the scope of the invention, the inventive composition is preferably an oil-in-water emulsion because the continuous phase is aqueous, creating a less greasy feel on the skin. It is well known in the art that actives in the larger, continuous aqueous phase of an oil-in-water emulsion have an increased probability of reaching the targeted tissues in the skin since the aqueous phase is in direct contact with the skin immediately upon application. See generally, Cosmetics Science and Technology at 47. In contrast, actives in the oil phase of an oil-in-water emulsion must first penetrate into the water phase and then into the skin. Therefore, the solubilized gum mastic is present in the aqueous phase of the inventive composition.
It is also well known in the art that oil solubility of an active enhances penetration of the active into the skin by virtue of mutual miscibility with the sebum present in the hair follicles and sebaceous glands. Cosmetics Science and Technology at 47. Solubilized gum mastic is soluble in oil. Thus, in the inventive compositions, the solubilized gum mastic is dissolved in a volatile, water miscible solvent such as ethanol, thereby remaining present in the continuous aqueous phase of the emulsion for immediate contact with the skin upon application. The volatile, water miscible solvents evaporate after application onto the skin, leaving the gum mastic supersaturated in the water phase of the emulsion. Supersaturation allows the gum mastic to remain in contact with the skin until penetration despite evaporation of the water phase after application.
The emulsion preferably contains at least 80 wt. % water, by weight of the vehicle. Preferably, the amount of water is at least 50 wt. % of the inventive composition, and most preferably from 60 to 80 wt. %, by weight of the composition.
Cosmetically Acceptable Vehicle:
The compositions according to the invention also comprise a cosmetically acceptable vehicle to act as a diluent, dispersant, or carrier for gum mastic in the composition, so as to facilitate its distribution when the composition is applied to the skin.
The vehicle may be aqueous, anhydrous or an emulsion. Preferably, the compositions are aqueous or an emulsion, especially water-in-oil or oil-in-water emulsion. Water when present will be in amounts which may range from 5 to 99%, preferably from 40 to 90%, optimally between 60 and 90% by weight.
Besides water, relatively volatile solvents may also serve as carriers within compositions of the present invention. Most preferred are monohydric C1-C3 alkanols. These include ethyl alcohol, methyl alcohol and isopropyl alcohol. The amount of monohydric alkanol may range from 1 to 70%, preferably from 10 to 50%, optimally between 15 and 40% by weight.
Emollient materials may also serve as cosmetically acceptable carriers. These may be in the form of silicone oils and synthetic esters. Amounts of the emollients may range anywhere from 0.1 to 50%, preferably between 1 and 20% by weight.
Silicone oils may be divided into the volatile and non-volatile variety. The term xe2x80x9cvolatilexe2x80x9d as used herein refers to those materials which have a measurable vapor pressure at ambient temperature. Volatile silicone oils are preferably chosen from cyclic or linear polydimethylsiloxanes containing from 3 to 9, preferably from 4 to 5, silicone atoms. Linear volatile silicone materials generally have viscosities less than about 5 centistokes at 25xc2x0 C. while cyclic materials typically have viscosities of less than about 10 centistokes. Nonvolatile silicone oils useful as an emollient material include polyalkyl siloxanes, polyalkylaryl siloxanes and polyether siloxane copolymers. The essentially non-volatile polyalkyl siloxanes useful herein include, for example, polydimethyl siloxanes with viscosities of from about 5 to about 25 million centistokes at 25xc2x0 C. Among the preferred non-volatile emollients useful in the present compositions are the polydimethyl siloxanes having viscosities from about 10 to about 400 centistokes at 25xc2x0 C.
Among the ester emollients are:
(1) Alkenyl or alkyl esters of fatty acids having 10 to 20 carbon atoms. Examples thereof include isoarachidyl neopentanoate, isononyl isonanonoate, oleyl myristate, oleyl stearate, and oleyl oleate.
(2) Ether-esters such as fatty acid esters of ethoxylated fatty alcohols.
(3) Polyhydric alcohol esters. Ethylene glycol mono and di-fatty acid esters, diethylene glycol mono- and di-fatty acid esters, polyethylene glycol (200-6000) mono- and di-fatty acid esters, propylene glycol mono- and di-fatty acid esters, polypropylene glycol 2000 monooleate, polypropylene glycol 2000 monostearate, ethoxylated propylene glycol monostearate, glyceryl mono- and di-fatty acid esters, polyglycerol poly-fatty esters, ethoxylated glyceryl monostearate, 1,3-butylene glycol monostearate, 1,3-butylene glycol distearate, polyoxyethylene polyol fatty acid ester, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters are satisfactory polyhydric alcohol esters.
(4) Wax esters such as beeswax, spermaceti, myristyl myristate, stearyl stearate and arachidyl behenate.
(5) Sterols esters, of which cholesterol fatty acid esters are examples thereof.
Fatty acids having from 10 to 30 carbon atoms may also be included as cosmetically acceptable carriers for compositions of this invention. Illustrative of this category are pelargonic, lauric, myristic, palmitic, stearic, isostearic, hydroxystearic, oleic, linoleic, ricinoleic, arachidic, behenic and erucic acids.
Humectants of the polyhydric alcohol type may also be employed as cosmetically acceptable carriers in compositions of this invention. The humectant aids in increasing the effectiveness of the emollient, reduces scaling, stimulates removal of built-up scale and improves skin feel. Typical polyhydric alcohols include glycerol, polyalkylene glycols and more preferably alkylene polyols and their derivatives, including propylene glycol, dipropylene glycol, polypropylene glycol, polyethylene glycol and derivatives thereof, sorbitol, hydroxypropyl sorbitol, hexylene glycol, 1,3-butylene glycol, 1,2,6-hexanetriol, ethoxylated glycerol, propoxylated glycerol and mixtures thereof. For best results the humectant is preferably propylene glycol or sodium hyaluronate. The amount of humectant may range anywhere from 0.5 to 30%, preferably between 1 and 15% by weight of the composition.
Thickeners may also be utilized as part of the cosmetically acceptable carrier of compositions according to the present invention. Typical thickeners include crosslinked acrylates (e.g. Carbopol 982), hydrophobically-modified acrylates (e.g. Carbopol 1382), cellulosic derivatives and natural gums. Among useful cellulosic derivatives are sodium carboxymethylcellulose, hydroxypropyl methylcellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, ethyl cellulose and hydroxymethyl cellulose. Natural gums suitable for the present invention include guar, xanthan, sclerotium, carrageenan, pectin and combinations of these gums. Amounts of the thickener may range from 0.0001 to 5%, usually from 0.001 to 1%, optimally from 0.01 to 0.5% by weight.
Collectively, the water, solvents, silicones, esters, fatty acids, humectants and/or thickeners will constitute the cosmetically acceptable carrier in amounts from 1 to 99.9%, preferably from 80 to 99% by weight.
An oil or oily material may be present, together with an emulsifier to provide either a water-in-oil emulsion or an oil-in-water emulsion, depending largely on the average hydrophilic-lipophilic balance (HLB) of the emulsifier employed.
Surfactants may also be present in cosmetic compositions of the present invention. Total concentration of the surfactant will range from 0.1 to 40%, preferably from 1 to 20%, optimally from 1 to 5% by weight of the composition. The surfactant may be selected from the group consisting of anionic, nonionic, cationic and amphoteric actives. Particularly preferred nonionic surfactants are those with a C10-C20 fatty alcohol or acid hydrophobe condensed with from 2 to 100 moles of ethylene oxide or propylene oxide per mole of hydrophobe; C2-C10 alkyl phenols condensed with from 2 to 20 moles of alkylene oxide; mono- and di-fatty acid esters of ethylene glycol; fatty acid monoglyceride; sorbitan, mono- and di-C8-C20 fatty acids; block copolymers (ethylene oxide/propylene oxide); and polyoxyethylene sorbitan as well as combinations thereof. Alkyl polyglycosides and saccharide fatty amides (e.g. methyl gluconamides) are also suitable nonionic surfactants.
Preferred anionic surfactants include soap, alkyl ether sulfate and sulfonates, alkyl sulfates and sulfonates, alkylbenzene sulfonates, alkyl and dialkyl sulfosuccinates, C8-C20 acyl isethionates, acyl glutamates, C8-C20 alkyl ether phosphates and combinations thereof.
Various types of active ingredients may be present in cosmetic compositions of the present invention. Actives are defined as skin benefit agents other than emollients and or ingredients that merely improve the physical characteristics of the composition. Although not limited to this category, general examples include anti-acne agents, additional anti-sebum agents, and sunscreens.
Anti-acne agents include but are not limited to benzoyl peroxide (up to 20 wt. % may be included), retinoids (typically 0.025%-0.05%), salicylic acid (typically up to 2 wt. %), and sulphur (up to 8 wt. %).
Retinoids increase collagen synthesis by dermal fibroblasts. This results in protection from sun damage and smoothening of wrinkled skin. The term xe2x80x9cretinoidsxe2x80x9d as used herein includes retinoic acid, retinol, retinal, and retinyl esters. Included in the term xe2x80x9cretinoic acidxe2x80x9d are 13-cis retinoic acid and all-trans retinoic acid.
The term xe2x80x9cretinolxe2x80x9d as used herein includes the following isomers of retinol: all-trans-retinol, 13-cis-retinol, 11 -cis-retinol, 9-cis-retinol, 3, 4-didehydro-retinol. Preferred isomers are all-trans-retinol, 13-cis-retinol, 3,4-didehydro-retinol, 9-cis-retinol, 9-cis-retinol. Most preferred is all-trans-retinol, due to its wide commercial activity.
Retinyl ester is an ester of retinol. The term xe2x80x9cretinolxe2x80x9d has been defined above. Retinyl esters suitable for use in the present invention are C1-C30 esters of retinol, preferably C2-C20 esters, and most preferably C2, C3, and C16 esters because they are more commonly available. Examples of retinyl esters include but are not limited to: retinyl palmitate, retinyl formate, retinyl acetate, retinyl propionate, retinyl butyrate, retinyl valerate, retinyl isovalerate, retinyl hexanoate, retinyl heptanoate, retinyl octanoate, retinyl nonanoate, retinyl decanoate, retinyl undecandate, retinyl laurate, retinyl tridecanoate, retinyl myristate, retinyl pentadecanoate, retinyl heptadeconoate, retinyl stearate, retinyl isostearate, retinyl nonadecanoate, retinyl arachidonate, retinyl behenate, retinyl linoleate, retinyl oleate, retinyl lactate, retinyl glycolate, retinyl hydroxy caprylate, retinyl hydroxy laurate, retinyl tartarate.
Sunscreens include those materials commonly employed to block ultraviolet light. Illustrative compounds are the derivatives of PABA, cinnamate and salicylate. For example, octyl methoxycinnamate and 2-hydroxy-4-methoxy benzophenone (also known as oxybenzone) can be used. Octyl methoxycinnamate and 2-hydroxy-4-methoxy benzophenone are commercially available under the trademarks, Parsol MCX(copyright) and Benzophenone-3(copyright), respectively. The exact amount of sunscreen employed in the compositions can vary depending upon the degree of protection desired from the sun""s UV radiation.
Many cosmetic compositions, especially those containing water, must be protected against the growth of potentially harmful microorganisms. Preservatives are, therefore, necessary. Suitable preservatives include alkyl esters of p-hydroxybenzoic acid, hydantoin derivatives, propionate salts, and a variety of quaternary ammonium compounds. Particularly preferred preservatives of this invention are methyl paraben, propyl paraben, phenoxyethanol and benzyl alcohol. Preservatives will usually be employed in amounts ranging from about 0.1% to 2% by weight of the composition.
Powders may be incorporated into the cosmetic composition of the invention to aid in oil control. These powders include chalk, talc, Fullers earth, kaolin, starch, smectites clays, chemically modified magnesium aluminum silicate, organically modified montmorillonite clay, hydrated aluminum silicate, fumed silica, aluminum starch octenyl succinate and mixtures thereof.
Other adjunct minor components may also be incorporated into the cosmetic compositions. These ingredients may include coloring agents, opacifiers and perfumes. Amounts of these other adjunct minor ingredients may range anywhere from 0.001% up to 20% by weight of the composition.
Use of the Composition:
The composition according to the invention is intended primarily as a product for topical application to human skin, especially as an agent for controlling or preventing oily skin, for improving skin""s radiance and clarity and finish, and for preventing or reducing the appearance of wrinkled, dry, aged or photoaged skin.
In use, a quantity of the composition, for example from 1 to 100 ml, is applied to exposed areas of the skin, from a suitable container or applicator and, if necessary, it is then spread over and/or rubbed into the skin using the hand or fingers or a suitable device.
Product Form and Packaging:
The cosmetic skin composition of the invention can be in any form, e.g. formulated as a toner, gel, powder, mask, solid bar, adhesive patch, mousse, nonwoven or woven substrate (wipe), lotion, a fluid cream, or a cream.
The composition can be packaged in a suitable container to suit its viscosity and intended use by the consumer. For example, a lotion or fluid cream can be packaged in a bottle or a roll-ball applicator or a propellant-driven aerosol device or a container fitted with a pump suitable for finger operation. When the composition is a cream, it can simply be stored in a non-deformable bottle or squeeze container, such as a tube or a lidded jar. The invention accordingly also provides a closed container containing a cosmetically acceptable composition as herein defined.
The composition may also be included in capsules such as those described in U.S. Pat. No. 5,063,057, incorporated by reference herein.